Method and apparatus for actuating downhole devices

ABSTRACT

To actuate downhole devices in accordance with the disclosure, fluid is pumped through the drill string at a rate that creates a preselected pressure condition in the drill string. At such preselected pressure condition, a timer is actuated that continues to run as long as the preselected pressure condition exists. If the pressure condition is maintained for a length of time sufficient for the timer to time out, the downhole device will be actuated. The device is deactuated by circulating fluid through the drill string to create a second pressure condition that actuates a timer that runs as long as the preselected pressure condition is maintained. When the timer times out, it deactivates the device. In another embodiment, the particular device to be actuated is selected by rotation of the drill string after the timer times out. It is deactuated by creating a particular flow condition until the timer times out. A third embodiment permits selection of simultaneous functions by the flow-time method and deactuation by stopping fluid circulation.

United States Patent 11 1 1111 3,896,667

Jeter July 29, 1975 [54] METHOD AND APPARATUS FOR I [57] ABSTRACTACTUATING DOWNHOLE DEVICES To actuate downhole devices in accordancewith the [75] Inventor: John D. Jeter, Midland, Tex. disclosure, fluidis pumped through the drill string at a rate that creates a preselectedpressure condition in the drill string. At such preselected pressurecondi- [22] Filed: Oct. 26, 1973 tion, a timer is actuated thatcontinues to run as long as the preselected pressure condition exists.It the [2]] Appl' 409310 pressure condition is maintained for a lengthof time sufficient for the timer to time out, the downhole de- [73]Assignee: Texas Dynamatics, Inc., Dallas, Tex.

[52] US. Cl 715/151; 175/40 vice will be actuated. The device isdeactuated by cir- [51] Int. Cl E21b 47/00 culating fluid through thedrill string to create a sec- [58] Field of Search 73/ 151; 175/40, 50;0nd pressure condition that actuates a timer that runs 340/18 NC, 18 LD,l8 CM as long as the preselected pressure condition is maintained. Whenthetimer times out, it deactivates the [56] References Cited v device.In another embodiment, the particular device UNITED STATES PATENTS to beactuated is selected by rotation of the drill string 2 415 249 2/1947Kothny 73/151 ux after the timer times is actuated by creating aparticular flow condition until the timer times out. A

2,681,567 6/1954 Widess 73/151 2,924,432 2/l960 Arps et al. 73/151 thlrdembodiment permits selection of simultaneous functions by the flow-timemethod and deactuation by Primary Examiner-Jerry W. Myracle pping fl ii1fCulati0n.

F f d Th Attorney, Agent, or trm Barg re e and ompson 8 Clai s, 11 a ingF gu es PATENTEI] JUL 2 9 I975 SHEET 6 D 3 m D, E H w c K 6AM ml u- E moMESA: Eqm \SQE FIG.4

TIME

PATENTEUJULZSISYS 3, 896.667

UL-LLI U T FIGEB i es 05 85 METHOD AND APPARATUS FOR ACTUATINGDOWNI-IOLE DEVICES This invention relates to a method of and apparatusfor actuating one or more downhole devices carried by a drill string.

There is a need from time to time in rotary drilling operations to causea downhole device carried by the drill string to do something or to stopdoing something. For example, if the drill string includes a fluid motorit may be desirable from time to time to lock the rotor of the motor tothe stator so the assembly attached to the rotor can be rotated by thedrill string and to later unlock the rotor for continued drillingwithout having to pull the pipe string out of the hole. Another exampleis the periodic measurement of hole inclination and azimuthal direction.This is done by lowering the measuring devices to the bottom of thedrill string from the surface. If these devices could be carried by thedrill string and turned on and off quickly, considerable down time wouldbe saved.

In Arps U.S. Pat. No. 2,924,432, entitled Earth Borehole Logging System,that issued Feb. 9, 1962, a system for actuating a downhole device isdisclosed. With this system, the device is actuated by cycling thepressure in the drill string between a low and a high value. Thus, theactuating apparatus is operated each time the circulation pressurefluctuates between the two values, as for example, when pumping isstopped to make a connection.

It is an object of this invention to provide a method of and apparatusfor actuating one or more downhole devices carried by the pipe stringthat requires a particular pressure condition to exist in the pipestring for a finite period of time before the device is actuated.

It is another object of this invention to provide a method of andapparatus for deactivating a downhole device carried by a pipe string bycreating a preselected pressure condition in the pipe string andmaintaining this pressure condition for a finite preselected period oftime whereby the device will not inadvertently be deactivated when thepressure is reduced to make a connection or raised back to normaldrilling pressure conditions.

It is a further object of this invention to provide a method of andapparatus for actuating a downhole device carried by a drill string thatcan be used to actuate the device when desired, but that otherwise isunaffected by normal drilling operations.

It is another object of this invention to provide a method of andapparatus for actuating a selected one of a plurality of downholedevices carried by a drill string by maintaining-preselected pressureconditions in the drill string for a finite preselected period of time.

These and other objects, advantages, and features of this invention willbe apparent to those skilled in the art from a consideration of thespecification, including the attached drawings and appended claims.

In the drawings:

FIGS. 1A and 1B are vertical sectional views through a preferredembodiment of the apparatus of this invention:

FIG. 2 is a circuit diagram showing the electrical system used in theembodiment of FIGS. 1A and 18;

FIG. 3 is a graph of time versus flow rate or pressure;

FIG. 4 is a graph of time versus voltage;

FIGS. 5A and 5B are vertical sectional views through an alternateembodiment of the apparatus of this invention;

FIG. 6 is a vertical sectional view through another alternate embodimentof this invention;

FIG. 7 is a cross-sectional view taken along line 7of FIG. 6; and

FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. 6.

In the embodiment shown in FIGS. 1A and 1B, tubular body or housing 10is located in pipe string '11 at the desired position. which willusually be adjacent the lower end of the string. It can be held inposition in any convenient manner. Located adjacent the upper end ofbody 10 is orifice 12 to cause a pressure drop in fluid flowing throughthe orifice. Upstream of orifice 12, when fluid is pumped down the pipestring in the conventional manner, is tubular diaphragm 13. The oppositeends of the diaphragm are in sealing engagement with body 10 with theportion in between spaced from the body to form annular cavity 14.

Mounted below orifice 12in body 10 is instrument housing 15. A pluralityof electrical components are located in cavity 16 of the instrumenthousing. including pressure sensitive switch assemblies 17 and 18.Cavity 16 of the instrument housing is connected to annular cavity 14above orifice 12 by passageway 19. By filling annular cavity 14 of thepassageway with a liquid, such as oil, the pressure above orifice 12will be transmitted to the upper end of cavity 16 and directed to actagainst pressure switch assemblies 17 and 18. These pressure sensitiveswitches could be of the type that are actuated by a given staticpressure coming from one source, such as annular space 14. Preferably,however, the switches are actuated by the differential pressure createdby the pressure drop in the fluid flowing through orifice 12. Theswitches then are independent of hydrostatic pressure, which will varydepending on the position of the switches in the well bore. Eachassembly includes two switches connected in series. One is normally openand closes at a first preselected pressure differential. The other isnormally closed and opens at a second preselected pressure differential.When the pressure differential is between the first and second pressuredifferen- .tials, the switch assembly is closed and current can flowtherethrough.

Therefore, instrument housing 15 has section 15a of reduced diamterlocated inside of cylindrical screen 21 that is surrounded by tubulardiaphragm 20. The opposite ends of the diaphragm are sealed to theinstrument housing with the portion in between spaced from the housingto provide annular chamber 22. With this chamber filled with a liquid,such as oil, the pressure in pipe string 11 adjacent the instrumenthousing is transmitted to space 16 through passageway 22a. Pressureswitch assemblies 17 and 18 are arranged to sense the difference in thepressure in passageways 19 and 22a that is created by the pressure dropacross orifice 12 when fluid is pumped down drill string 11. The amountof pressure drop is dependent upon the rate of flow and other factors,such as the viscosity of the fluid being pumped.

In accordance with this invention, timing means are provided that willoperate while certain pressure conditions exist in the pipe string. Inthe embodiment shown, such'timing means include R-C timing circuit 23(enclosed by dashed line box), as shown in FIG. 2. The

timing circuit is actuated when the pressure differential across orifice12 is within the preselected range that closes pressure switch assembly17 and connects R-C circuit 23 to battery 24. As long as the pressuredifferential stays within the preselected range, the battery will supplyelectrical energy to the timing circuit until such time as the charge oncapacitor 25 has reached the point that it will actuate relay 26. Thetime required for this to occur is determined by the circuit components,but it should be long enough to allow the pressure differential acrossorifice 12 to move back and forth through the range, as occurs duringnormal drilling operations, without causing the circuit to time out,i.e., actuate relay 26.

The relay drops the timing circuit out and energizes solenoid 27 andstepping switch solenoid 28a. The stepping switch solenoid movesstepping switch 28 into position to actuate a downhole device. Aplurality of such devices could be used with the stepping switch, witheach position of the switch designed to actuate a different device.

At the same time that the downhole device is being actuated, solenoid 27closes outlet 29a of hydraulic pump 29. This causes fluid from the pumpto travel through passageway 30, down the annular space between the pumphousing and cylinder 31 and through ports 32 into the bottom of thecylinder below piston 33. The fluid raises piston 33, and in doing soraises valve member 35 toward valve seat 36, which is actually thetapered downstream side of orifice 37. By nar rowing the distancebetween valve member 35 and valve seat 36, a pressure pulse will becreated in the fluid being pumped down the pipe string. The pressurepulse can be detected at the surface and provides an indication that thedownhole device is now actuated.

Power is supplied to pump 29 by impeller 48. The impeller has vanes 480that cause hub 48b to rotate when drilling fluid is pumped down thedrill string. Output shaft 480 is connected to the hub and supported bypiston 33. Drive shaft 34 of the pump extends into and has a splinedconnection with output shaft 480. It can telescope into the output shaftas the piston moves, but is connected for rotation therewith by thesplines. Thus, rotation of the impeller by the flowing drilling fluiddrives pump 29.

The charge in capacitor 25 will hold relay 26 actuated long enough forthe solenoid and stepper switch to so function, after which the chargewill have bled down to the point that the relay will fall out. Ifpressure switch 17 is still closed by the pressure existing across it,R-C timing circuit 23 will be connected again to battery 24. If it isdesired to simply step stepper switch 28 one step and actuate thatdevice, then as soon as the signal of the pressure pulse reaches thesurface, the pressure differential across the switch should be changedso that switch 17 will open, otherwise the cycle will repeat itself andthe stepper switch will be stepped again, which could deactivate thedevice actuated by the first step of the switch. This would depend onthe arrangement of the stepper switch. Stepping the switch twice couldstop the first device actuated or not as desired. On the other hand, ifthe device that is to be actuated is at the third or fourth position ofthe switch, then by simply holding the pressure differential acrossswitch 17 such that switch 17 remains closed, then the circuit willsimply time out three or four times stepping the stepper switch three orfour times, after which when the third or fourth pressure pulse reachesthe surface, the operator can change the pressure conditions and openthe switch.

Means are provided to stop the actuated downhole device or devices whena preselected pressure condition exists in the drill pipe. This is thefunction of pressure switch 18, second R-C timing circuit 38, and relay39 of FIG. 2. A pressure drop within a preselected range is createdacross orifice 12. This closes switch assembly l8 connecting R-C timingcircuit 38 to battery 24. When the charge has built-up on the condenserof the circuit sufficiently to actuate relay 39, erasing solenoid 40will be actuated, releasing stepper switch 28 to be returned by springsor the like to its original position. This deactivates all devices.

The electrical components described above are supplied with power bybattery 24 in this embodiment. Generator 42 supplies charging current tothe battery to keep it charged. The generator is operated by verticalvibrations of the pipe string, which will be substantial if the pipestring, for example, is being employed in a drilling operation. Thegenerator is shown schematically and includes coils 43 and 44. They arelocated in the magnetic field of magnets 45 so that relative movement ofthe coils and the magnets will induce a current in the coils that can beused to charge battery 24. In the embodiment shown, the magnets aremounted on springs 46 so that their inertia will cause them to tend toremain stationary while the pipe moves the coils thereby producing thedesired relative movement of the magnetic field and the coils to inducea current. Diode 47 rectifies the induced current to provide a DCcharging current to the battery.

FIG. 3 shows graphically the relationship of flow rate or pressure dropacross orifice 12 versus time. FIG. 4 shows graphically the voltagebuild up on capacitor 25 or 38a, as the case may be, versus time, InFIG. 3, curve A shows the pressure drop across orifice 12 as the drillerbrings his circulation rate from zero up to normal drilling rates. Indoing so, the pressure drop across the orifice will for short periods bein pressure ranges E and F, during which times pressure switchassemblies 17 and 18 will be closed. The length of time that each isclosed, however, is insufficient to,allow time delay circuits 23 and 38,respectively, to actuate relays 26 and 39, so nothing happens. Thus, thedriller can bring his flow rate up to that of normal drilling orcirculate drilling fluid for any purpose and as long as he passesthrough pressure ranges E and F before the timing circuits time out, thestepper switch will be unaffected. When such circulation is stopped, thepressure will drop through these ranges, of course, but again will notbe in the ranges long enough to actuate the stepper switch.

Should the driller desire to step switch 28 to actuate one or moredownhole devices in his drill string, he adjusts the flow rate toproduce a pressure drop within pressure range E. This closes switch 17and energizes timing circuit 23. For example, curve B of FIG. 3illustrates such an operation. The driller brings the flow rate up fromzero. He enters pressure range E, then exceeds it slightly. During thetime that the pressure drop is out of the range, switch 17 will beturned off. The pressure drop then stabilizes within the range andswitch assembly 17 remains closed and a charge builds up on capacitor25.

FIG. 4 illustrates the build up of voltage on the capacitor versus time.This is shown with curve C. The square-shaped curve D is representativeof the periods of time that the pressure switch 17 is closed. Thus,during the first brief period D, that switch 17 is closed, a smallamount of voltage builds up on the capacitor. Then, the switch is offagain for a short period of time and some of the charge drains off.During time interval D voltage builds up to the point where relay 26 isactuated. As explained above, this cuts off the source of power to thetiming circuit, as shown by the gap between D and D and the voltage onthe capacitor begins to drain off. When solenoid 27 causes pump 29 tomove valve element 35 up far enough to cause a pressure pulse, thiswill, of course, affect the rate of flow of.

fluid through the drill pipe and may cause the pressure drop acrossorifice 12 to drop to a point out of the pressure range E, as indicatedin FIG. 3 by curve B. This is a very short interval and is just amomentary change in the pressure drop. [f the flow rate is maintained,the pressure drop will move again into range E and the cycle will berepeated.

Curve B is shown moving from range E to range F which is the pressurerange that closes pressure switch assembly 18. Here again, forillustration purposes, the curve of Delta P is shown dropping throughthe range closing the switch momentarily (time period D but long enoughto start a build up of charge on capacitor 380, then returning into thepressure zone and holding switch 18 closed long enough (time period Dfor time delay circuit 38 to time out. When this occurs, as explainedabove, relay 39 will return stepper switch 28 to its original startingpoint, deactuating all of the devices previously actuated, which, in theexample shown, would be the two or more that are actuated by the firstand second positions of the stepper switch.

In the example described, the flow rates are adjusted to cause timingcircuit 23 to time out in sequence and step switch 28 twice. Bymaintaining this flow rate, the switch can be stepped as many times asdesired. Also, after the downhole device is actuated, the driller maywant to return to normal flow rates. This he can do and even stoppumping altogether to make a connection or whatever without affectingswitch 28. At a later time, he can return the flow rate to provide apressure drop within range F and deactuate the device.

As explained above, solenoid 27 closes outlet 29a of pump 29 directingthe discharge of the pump under piston 33 to raise valve element 35 andcreate a pressure signal in the fluid stream. The closer the valveelement comes to valve seat 36, the greater the pressure drop for agiven flow rate. This increases the upward force required of piston 33and the pressure of the fluid under the piston. Usually, solenoid 27will be deenergized before the pressure drop builds up too much or thepassageway is closed off. However, to be safe, check valve 49 isdesigned to release the fluid pressure under the piston when it reachesa preselected amount.

The alternate embodiment of the invention, shown in FIGS. 5A and 5B, isdesigned to also actuate a device when a differential pressure within apreselected range is applied to the apparatus and maintained for apredetermined finite period of time. The apparatus is all carried bypipe section 50 in which is located instrument housing 51. Housing 51 isshown in one piece for simplicity, although in practice it wouldprobably consist of many separate parts. The upper end portion 51a oftubular member 51 has opening 52 of reduced diameter to provide a flowrestriction for the fluid being pumped through the pipe string. Pipejoint is connected into a pipe string in the conventional manner.Housing 51 maybe held in axial position within pipe joint 50 by tooljoints or any suitable method.

Combining with orifice 52 to restrict the flow of fluid through theorifice is valve element 53 that is supported by rod 54. The rod extendsthrough the valve element and is connected to cap 55 that holds thevalve element in position on the rod against upwardly facing shoulder56. The valve element telescopes over annular guide 57 which is anintegral part of housing 51.

Valve rod 54 extends through guide 57 and into cylinder 60. Piston 6l islocated in the cylinder and attached to the rod to cause the rod to movewhen the piston is subjectedto a different pressure in the cylinder. Therod extends downwardly into elongated opening 62 in selector-valve body5111. Valve rod 54 has central opening 54a of relatively large diameterthat extends from the lower end to where it connects with centralopening 54b of smaller diameter in the upper portion of the rod. Coilspring 64 is located in opening 54a with one end engaging partition 58.The other end engages the bottom of opening 62 to resiliently urge therod and valve element 53 upwardly into position to restrict the flow offluid through orifice 52. When fluid is being pumped down the pipestring, the pressure of the fluid upstream of orifice 52 will actagainst valve element 53 and urge it downwardly against the upward forceof spring 64. The fluid upstream can also enter cap 55 through ports 55aand pass through lateral ports 54c into central opening 54b of the valverod. From opening 54b, the fluid can flow into cylindrical cavity 53a ofvalve element 53 through passageway or opening 54a and port 54d. Thefluid entering cavity 53a will be at substantially the same pressure asthe fluid upstream of orifice 52 and will act upwardly against the upperend of cavity 53a to resist downward movement of valve element 53'. Theclearance between guide 57 and valve element 5.3 is such that it willsufficiently restrict the flow of fluid from cylindrical cavity 53a thatpressure will build up in the cavity and exert such an upward force.

For a given flow rate then, valve element 53 will move valve rod 54downwardly to a given position, such as the one shown in FIG. 5A. Inthis position, port 65 in the lower end of the rod will be in alignmentwith annular groove 66 on the wall of opening 62. This allows fluid fromupstream of orifice 52 to flow into chamber 69 through lateral port 68.Within the physical space limitations available, any given number ofports 68 and chambers 69 can be provided, each one designed to actuate adifferent downhole device, as will be described below. As to whichdevice is to be actuated, of course, it will depend upon the position ofrod 54 and this, in turn, is dependent upon the rate of flow of fluidthrough orifice 52.

Located in chamber 69 is bellows 70. The upper end of the bellows isconnected to rod 71, which extends through bellows base 72. Cylindricalbody portion 51h of housing 51, in which cavity 69 is located, includesannular flange 74 to support the base of the bellows in the cavity. Nuts75, in engagement with threads on the lower end of the base, clamp thebellows base to the annular flange. Seal ring 76 prevents the flow offluid from chamber 69 past the bellows base. In this embodiment of theinvention, this bellows assembly provides the timer for the apparatus.

The fluid in chamber 69 is at or a little below upstream pressure. Thefluid inside bellows 70 and in chamber 77 below the bellows ismaintained at the pressure adjacent this portion of the apparatus, whichis downstream of the orifice and a lower pressure than that upstream.The pressure differential across bellows 70 will cause it to collapse orcontract moving rod 71 downward through the central opening in base 72.This will displace fluid from inside the bellows into chamber 77 throughthe annular space between the rod and the opening in the base.

For pressure differentials within a preselected range. the annular spacecan be designed to require a finite minimum period of time for asufficient volume of the fluid in bellows 70 to be displaced for rod 71to move into engagement with rod 82. The upper end of bellows 81 isattached to rod 82 and the lower end is attached to bellows base 83 toprovide a seal between the rod and bellows base 83 while allowing therod to reciprocate. Snap ring 84 supports the base and bellows in thelower end of chamber 77. Seal ring 83a is carried by the base tomaintain a seal between the bellows base and body 73.

Valve stem 87 extends into chamber 77 in axial alignment with rod 82 andwith its upper end adjacent the lower end of the rod. The valve stemextends downwardly through openings 85 and 86 into chamber 94. The lowerend of the stem is connected to valve head 88 which engages seat 88a andisolates opening 86 from chamber 94. Valve head 88 is held against itsseat by coil spring 89.

The apparatus just described is designed for bellows rod 82 to be moveddownwardly by rod 71 after a predetermined period of time and move valveelement 88 away from seat 88a. This allows fluid to flow from chamber 94to passageway 91 which causes fluid pressure to be supplied to thedevice to be actuated in a manner described below. Chamber 94 issupplied with fluid at upstream pressure from chamber 98 by port 93.Passageway 101 conducts fluid at upstream pressure from chamber 62 tochamber 98. Piston 97 is located in chamber 98 for purposes to bedescribed below, but port 97a in the piston allows fluid to flow to port93 with only a small pressure drop. Passageway 92 connects chamber 94 toambient pressure at all times to help keep a pressure differential frombuilding up between the inside cavities of the housing and the outsidewhen the apparatus is not being operated. The diameter of passageway 92is such that the flow of fluid through it will not appreciably drop thepressure in chamber 94. Appropriate seals (not shown) are provided toisolate passageway 91 from the pressure in chamber 94 except when valve88 is open. Thus. with the apparatus described, for a given flow rateand pressure drop across orifice 52 that is held for a predeterminedfinite period of time. the downhole device can be actuated.

As bellows 70 moves rod 71 downward into engagement with rod 82, fluidis displaced from bellows 70 into chamber 77. To keep the pressure inchamber 77 from increasing above ambient, an arrangement (not shown)like sleeve described above and shown in FIG. 1A can be used.

Means are provided to hold valve element 88 open after upstream pressureis removed from above bellows so that the device will continue to beactuated, while other flow rates are selected to actuate additionaldevices or to return to drilling operations or the like. In theembodiment shown, pin or pawl is urged to the right by coil spring 95 sothat the sharp edge on the end of the pawl will engage thecircumferential grooves 96 in the valve stem. Grooves 96 have flat wallson their low side and tapered walls on the upper side. These taperedwalls will cam the pawl to the left and out of the way as the valve stemmoves down to open the valve. The flat walls, however. will not exert alateral force on the pawl and the pawl will prevent upward movement ofthe valve stem and hold the valve open.

Some means should be provided to close the valve when it is desired tocancel the operation of the device. in the embodiment shown. piston 97is located in chamber 98 of housing area 5111 and its upper end has asharp circular edge to engage bevel 99 on the pawl. Coil spring 100urges piston 97 upward from the position shown which movement will causeits upper end to cam pawl 94 to the left. Such movement will releasevalve stem 87 for upward movement, allowing spring 89 to close the valveand deactivate the device. In this embodiment, the device will bedeactivated when there is no flow through the pipe string. When there isflow, fluid from the inside of chamber 62, which is at the pressure ofthe fluid upstream of orifice 52, can flow downwardly through passageway101 and act against piston 97 urging it downwardly to the position shownwhere pawl 94 is free to move to the right to hold the valve open. Whenflow is stopped, the pressure across piston 97 equalizes and spring 98will move it upwardly causing it to cam the pawl to the left and releasethe valve stem, thereby deactivating the downhole device.

It may be preferable to provide a time delay between the stopping offlow and the release of the valve stem to allow circulation to bestopped momentarily. as when adding another joint to the pipe string,without deactuating the device. This can be done, for example, by usinga double bellows arrangement like bellows 70 and 81 to move a beveledsurface to cam pawl 90 to the left after a predetermined period of time.

As explained above, the position of control rod 54 determined which ofthe plurality of grooves 66 is supplied with actuating pressure andwhich of the plurality of downhole devices is actuated. The position ofthe control rod is determined by the pressure drop through orifice 52,which is a function of the rate that fluid is pumped through the pipestring. Thus, for each position of the control rod, the pressureupstream of orifice 52 will be different and the pressure of theactuating fluid supplied to passageway 91 will be different.

It may be desirable or necessary to supply each downhole device withactuating fluid having a pressure different from the pressure of thefluid in passageway 91. Therefore, it is one of the features of thisinvention to provide means for controlling the pressure of the actuatingfluid supplied to each of a plurality of devices. In the embodimentshown, passageway 91 extends downwardly through the cylindrical portionof the housing where it is connected to portion 51g of the housing thatis supported in the center of the housing by rib Sle. Portion 51f of thehousing provides orifice 107 through which the fluid flowing in the pipestring must pass. Valve element 108 is urged upwardly toward a positionto close orifice 107 by coil spring 109 that extends from the bottom ofbore 110 in housing portion 51g over which the valve member telescopes.The telescoping portion of the valve member is cylindrical skirt 112that forms cavity 113 between the upper end of housing portion 51g andvalve member 108. Fluid flowing through passageway 91 enters cavity 113through passageways 114, 115, 116, and 117.

Located in passageway or cavity 115 is flow restriction 118 that limitsthe rate fluid can flow into chamber 113. The cross-sectional areaagainst which the fluid acts in chamber 113 is greater than that oforifice 107 so that with sufficient pressure in chamber 113, the valveelement can be closed. As it is urged toward the closed position, theupstream pressure, of course, will increase providing passageway 91 withthe increased pressure upstream of the orifice. Consequently, byarranging check valve 119 to open at the preselected pressure desired,valve element 108 will be positioned by the upstream pressure fluid toproduce this pressure after which check valve 119 will open and thispressure will be maintained. The increase in upstream pressure and thepressure in passageway 91 caused by orifice 107 does not change theposition of control or selector rod 54 since the pressure differentialacross orifice 52 does not change, as both upstream and downstreampressure across this orifice are affected equally.

A plurality of devices may be supplied with fluid of different pressurewith this apparatus. Each device is connected to a passageway, such aspassageway 91, through which actuating fluid is supplied to the device.Each passageway is connected into chamber 113 through its own set ofcheck valves 119 and 120. As explained above, check valve 119 controlsthe pressure supplied to the device, whereas check valve 120 allows theother devices to be supplied with different pressures by keeping thepressure in chamber 113 from entering passageway 117 when thisparticular set of pas sageways is inoperative. Fluid continuously bleedsfrom chamber 113 through port 121 to insure that the valve elementdoesnt become locked in some position. The rate of flow of fluid throughport 121, however, is sufficiently low not to affect the overalloperation of the apparatus.

When not operating the apparatus, it is generally desirable to allowfluid to flow through the pipe string as freely as possible and with aminimum of restriction. Consequently, its another feature of thisinvention to provide means for moving valve element 53 substantially outof position to restrict the flow through orifice 52. In the embodimentshown, as the rate fluid is pumped increases toward normal circulationrates, the upstream pressure will increase and valve element 53 willmove control rod 54 downwardly until port 54d enters the bore of rodguide 57. The clearance between the rod and the bore of the rod guide issuch that the flow of fluid from port 54a' is reduced to the point whereit cannot build up pressure in chamber 53a. At the same time, port 540moves into the upper end of chamber 60 and now the fluid upstream oforifice 52 acts against piston 61 which will force valve element 53 androd 54 downwardly to the limit of their downward travel away fromorifice 52. This opens up the orifice to reduce to a minimum thepressure drop therethrough during times that the apparatus isinoperative. Check valves 122 and 123 in housing portions 51f and 51a,respectively, allow reverse circulation and also allow the pipe stringto fill up while it is being run into the hole.

In the other embodiment of the invention shown in FIGS. 6-8, all of theapparatus is located in housing 130, which consists essentially of uppercap 182, body 140, enclosure 132 and lower cap 183. As shown in FIGS. 7and 8, the housing is supported in the center of pipe string 13] by arms133 radially extending between the housing and cylindrical support 184.The natural pressure drop in the fluid flowing past the restriction toflow offered by the housing and support arms is employed to actuate thisdevice when given preselected pressure differentials are held forpredetermined finite periods of time.

Located in upper cap 182 of the housing is bellows 134. It is exposedexternally to the pressure of the fluid in the pipe string adjacent theupper end of the housing through one or more ports 135 extending throughthe cap. The upper end of the bellows is connected to disc 136. Rod 137is attached to the disc and extends through rod guide 138. The lower endof the bellows is attached to bellows base 139, which is integrallyattached to rod guide 138. The base of the bellows is connected to theupper end of body 140, and forms one wall of cavity 141 in the body. Thefluid in bellows 134 is discharged through ports 142 into cavity 141,when the pressure on the outside of the bellows exceeds that on theinside.

A pressure differential is created across the bellows when fluid ispumped down the drill pipe. The pressure on the outside of the bellowsis that of the fluid adjacent ports 135. Everything in body below valveandabove annular diaphragm 143 (FIG. 6B) is filled with fluid and sealedfrom the effect of outside pressure except through bellows 134, valve145, and flexible diaphragm 143. These two pressure sensing elements,bellows 134 and diaphragm 143, are spaced apart longitudinally in thehousing so that the ambient pressure at the upper end of the housing isgreater than that adjacent diaphragm 143, and it is this difference inpressure that is used to operate the apparatus by causing bellows 134 tocollapse forcing fluid out of the bellows into chamber 141.

Bellows 144 is locatedin cavity 141 with its lower end attached to body140. its upper end is attached to disc 145a of valve spool 145. Thebellows seals the upper end of elongated chamber 143 in which valvespool 145 is located. Cavity 141 has lower extension 147 that isconnected to valve chamber 143 by passageway 148 that divides into twobranches, an upper and a lower. The valve spool is in sealing engagementwith the wall of cavity 143 except for the two spaced portions ofreduced diameter. Passageway 146 connects valve chamber 143 to theinside of bellows 150 in cavity 153.

As shown, the valve spool is positioned to prevent the flow of fluidfrom cavity 147 to passageway 146. At a preselected differentialpressure across bellows 134 produced by a preselected flow rate, thepressure will build up in chamber 141 sufficiently to collapse bellows144 far enough to move the valve spool downwardly far enough to positionthe lower portion of reduced diameter of the spool adjacent the lowerbranch of passageway 147 and the upper end of passageway 146. The higherpressure fluid in cavities 144 and 147 will then flow to the inside ofbellows 150 through passageway 146. This will cause bellows base 151 andsplined rod 152 to move downwardly in chamber 153. Splined rod 152engages matching splines on eccentric weight 154.

The weight is mounted in cavity 155 by bearings 156 for free rotationaround the longitudinal axis of the housing. The lower end of splinedrod 152, when moved downwardly by bellows 150, moves into engagementwith gear 157 (FIG. 8). This gear is mounted on shaft 158. Pinion 159 ismounted on the shaft and is in engagement with gear 160, which in turnengages ring gear 161 mounted on the inside of the housing. Onewayclutch 162 prevents gear 157 and shaft 158 from rotating except in onedirection. The eccentric weight will seek the low side of the hole andtend to remain stationary as the pipe string is rotated. There willusually always be a low side. Ifthe well bore is substantially vertical,the tendency of the eccentric weight to remain stationary may not besufficient for the operation of the apparatus. If this is anticipated tobe a problem, a gyroscope can be substituted for the eccentric weight inthe manner described in my copending application, Ser. No. 409,176,filed Oct. 24, 1973.

With the gears in engagement with each other and with splined rod 152,rotation of the drill pipe will rotate ring gear 161 with it. Splinedrod 152 will remain stationary and gears 157 and 159 will walk aroundthe ring gear and splined rod, respectively, and in doing so, causevalve selector assembly 163 to rotate around its longitudinal axis,which also is the longitudinal axis of the pipe string.

The valve selector assembly includes shaft section 163a which extendsthrough valve body 164. Cam plate 165 is attached to the lower end ofshaft 163a. As shaft 163a rotates cam plate 165 relative to valve body164, cam 165a engages successively the stems of the valve elementscarried by valve body 164. As shown in FIG. 6, cam 165a is in engagementwith the stem of valve 166 and has raised it off its seat to allow fluidto flow from chamber 167 to passageway 168 which continues into spacermember 169. From there, the passageway passes through one of ribs 133 ofthe housing and downwardly to the device that this valve controls.Further rotation of the drill pipe will cause cam plate 165 to allowvalve 166 to close. Continued rotation will open valve 170 allowingfluid to move from cavity 167 to passageway 171 which, as shown in thedrawings, is connected to passageway 172 through spacer 169 and rib 133.Passageway 172 is connected to a downhole device to be actuated whenfluid under pressure is supplied to it through passageway 172.

The number of rotations of the drill pipe required to rotate cam plate165 to open valves 166 and 170 is known and is a function of the gearratio of the gear train between the ring gear rotated by the drill pipeand the splined rod. When cam plate 165 is in position to actuate thedesired device, normal operations can be resumed. Increased circulationwill provide an increase in the pressure drop across housing 130 andincrease the pressure drop across bellows 144. For normal drillingoperations, this is sufficient to move valve spool 145 to a position tocut off any further flow of fluid to any of the parts of the devicebelow the control valve. The spring action of bellows 150 will movesplined rod 152 upwardly out of engagement with gear 157 and rotation ofthe drill pipe will not affect the position of cam 165a. This allows thedevice selected to continue to operate while further operations arebeing performed, such as drilling.

To deactivate the device and return the apparatus to its startingposition, a particular flow rate is used to provide a pressuredifferential across bellows 144 that will position valve spool toconnect chamber 141 to passageway 173 through the upper branch ofpassageway 148. This introduces fluid at upstream pressure to theannular space between bellows 174 and 175 which moves bearing housing176 downwardly carrying valve selector assembly 163 with it. Suchmovement moves gear out of engagement with annular ring gear 161. Clockspring 177 has one end attached to selector assembly 163 by pin I78 andthe other end connected to stationary housing member 179 by pin 180.When gear 160 moves clear of the ring gear, spring 177 will rotate thevalve selector assembly, including cam plate 165, back to the positionwhere pin 178 is in engagement with stop 181. This places the cam platein a known position relative to the valves that control the downholedevices, and when it is desired to actuate a particular downhole device,the number of rotations of the drill pipe that are required to open thedesired valve will be known.

To avoid deactuating a device inadvertently while passing through thepumping rate that would position the valve spool to do this, passageway173 is of a diameter such that the flow of fluid through it, plus thecapacity of the space between bellows I74 and and the distance theselector assembly must move to disengage the gears, takes some time, theamount of which can be selected. Thus, there is a built-in time delaybefore a device can be deactuated.

From the foregoing, it will be seen that this invention is one welladapted to attain all of the ends and objects hereinabove set forth,together with other advantages which are obvious and which are inherentto the method and apparatus.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of theclaims.

As many possible embodiments may be made of the method and apparatus ofthis invention without departing from the scope thereof, it is to beunderstood that all matter herein set forth or shown in the accompanyingdrawings is to be interpreted as illustrative and not in a limitingsense.

The invention having been described, what is claimed 1. A method ofactuating a downhole device in a drill string comprising pumping fluiddown the drill string at a rate to provide a pressure drop across a flowrestriction within a preselected range that is different from the rangeof pressure drops produced during normal drilling operations,maintaining said pumping rate for a predetermined, finite, period oftime and actuating said downhole device at the end of the time period.

2. The method of claim 1 with the further step of creating a pressurepulse in the fluid in the drill string that is detectable at the surfacewhen the device is actuated.

3. The method of claim 1 with the further step of pumping fluid down thedrill string at a second rate to provide a pressure drop across a flowrestriction within a second different preselected range and maintainingsaid second rate for a predetermined, finite, period of time todeactuate said downhole device.

4. The method of claim 1 with the further step of stopping the pumpingof fluid to deactivate the downhole device.

5. A method of actuating one of a plurality of downhole devices carriedby a drill string comprising pumping fluid through the drill string tocreate a pressure drop across a flow restriction within one of severalpreselected ranges that are different from the range of pressure dropsproduced when pumping fluid during normal drilling operations,maintaining said pressure drop for a predetermined, finite period oftime and actuating one of said downhole devices at the end of the timeperiod.

6. A method of actuating a plurality of downhole devices carried by adrill string comprising pumping fluid through the drill string at a rateto create a pressure drop across a flow restriction within a preselectedrange that is different from the range of pressure drops produced duringnormal drilling operations, maintaining the pumping rate for apredetermined, finite period of time to actuate one of said devicesafter the time period has elapsed, and maintaining the pumping rate foradditional predetermined, finite periods of time to actuate another ofsaid devices for each additional elapsed time period the pumping rate ismaintained.

7. The method of claim 6 with the further steps of pumping at a secondrate to produce a second pressure drop across the flow restrictions andmaintaining said second pumping rate for a predetermined, finite periodof time to deactuate said devices.

8. A method of actuating one ofa plurality of devices carried by a drillstring comprising pumping fluid through the drill string to provide apressure differential, maintaining the pressure differential for apredetermined, finite, period of time, and rotating the drill string apredetermined number of revolutions to actuate said device.

9. The method of claim 8 with the further step of pumping fluid throughthe drill string at a rate to produce a second pressure drop andmaintaining said pumping rate for a predetermined, finite minimum periodof time to deactuate said device.

10. Apparatus for actuating a downhole device carried by a drill stringcomprising timing means carried by the drill string, means responsive toa preselected pressure condition in the drill string to cause the timingmeans to operate while said pressure condition exists, and means toactuate said downhole device when the timing means times out.

11. The apparatus of claim 10 further provided with means to deactuatethe device including a second timer, means to cause the second timer tooperate through a timing cycle when a second preselected pressurecondition exists, and means to deactivate the device when the secondtimer times out.

12. Apparatus for actuating a downhole device carried by a drill stringcomprising means for creating a pressure drop when fluid is pumped downthe drill string, a timer carried by the drill string, means responsiveto said pressure drop when it is within a preselected range to actuatethe timer and to allow it to operate as long as the pressure drop iswithin said range. and means to actuate said device when the timer timesout after a predetermined finite period of time.

13. The apparatus of claim 12 further provided with means to deactuatethe device including a second timer and means to actuate the timer andto allow it to operate as long as the pressure drop is within apreselected second range, and means to deactivate the device when thetimer times out after a predetermined finite period of time.

14. Apparatus for actuating a plurality of downhole devices carried by adrill string extending into a well bore, comprising timing means carriedby the drill string, means responsive to a preselected pressurecondition in the drill string to cause the timing means to operate whilesaid pressure condition exists, and means to actuate one of said deviceseach time the timing means times out.

15. The apparatus of claim 14 further provided with means for creating asurface detectable signal as each device is actuated.

16. The apparatus of claim 14 further provided with second timing means,means responsive to a preselected pressure condition in the drill stringto cause the second timing means to operate while said pressurecondition exists, and means for deactivating said devices when thesecond timer times out.

17. The apparatus of claim 14 in which the means to actuate one of saiddevices includes means responsive to rotation of the drill string toactuate additional devices.

18. The apparatus of claim 14 further provided with means to provide apreselected pressure differential for each of the devices when actuated.

1. A method of actuating a downhole device in a drill string comprisingpumping fluid down the drill string at a rate to provide a pressure dropacross a flow restriction within a preselected range that is differentfrom the range of pressure drops produced during normal drillingoperations, maintaining said pumping rate for a predetermined, finite,period of time and actuating said downhole device at the end of the timeperiod.
 2. The method of claim 1 with the further step of creating apressure pulse in the fluid in the drill string that is detectable atthe surface when the device is actuated.
 3. The method of claim 1 withthe further step of pumping fluid down the drill string at a second rateto provide a pressure drop across a flow restriction within a seconddifferent preselected range and maintaining said second rate for apredetermined, finite, period of time to deactuate said downhole device.4. The method of claim 1 with the further step of stopping the pumpingof fluid to deactivate the downhole device.
 5. A method of actuating oneof a plurality of downhole devices carried by a drill string comprisingpumping fluid through the drill string to create a pressure drop acrossa flow restriction within one of several preselected ranges that aredifferent from the range of pressure drops produced when pumping fluidduring normal drilling opeRations, maintaining said pressure drop for apredetermined, finite period of time and actuating one of said downholedevices at the end of the time period.
 6. A method of actuating aplurality of downhole devices carried by a drill string comprisingpumping fluid through the drill string at a rate to create a pressuredrop across a flow restriction within a preselected range that isdifferent from the range of pressure drops produced during normaldrilling operations, maintaining the pumping rate for a predetermined,finite period of time to actuate one of said devices after the timeperiod has elapsed, and maintaining the pumping rate for additionalpredetermined, finite periods of time to actuate another of said devicesfor each additional elapsed time period the pumping rate is maintained.7. The method of claim 6 with the further steps of pumping at a secondrate to produce a second pressure drop across the flow restrictions andmaintaining said second pumping rate for a predetermined, finite periodof time to deactuate said devices.
 8. A method of actuating one of aplurality of devices carried by a drill string comprising pumping fluidthrough the drill string to provide a pressure differential, maintainingthe pressure differential for a predetermined, finite, period of time,and rotating the drill string a predetermined number of revolutions toactuate said device.
 9. The method of claim 8 with the further step ofpumping fluid through the drill string at a rate to produce a secondpressure drop and maintaining said pumping rate for a predetermined,finite minimum period of time to deactuate said device.
 10. Apparatusfor actuating a downhole device carried by a drill string comprisingtiming means carried by the drill string, means responsive to apreselected pressure condition in the drill string to cause the timingmeans to operate while said pressure condition exists, and means toactuate said downhole device when the timing means times out.
 11. Theapparatus of claim 10 further provided with means to deactuate thedevice including a second timer, means to cause the second timer tooperate through a timing cycle when a second preselected pressurecondition exists, and means to deactivate the device when the secondtimer times out.
 12. Apparatus for actuating a downhole device carriedby a drill string comprising means for creating a pressure drop whenfluid is pumped down the drill string, a timer carried by the drillstring, means responsive to said pressure drop when it is within apreselected range to actuate the timer and to allow it to operate aslong as the pressure drop is within said range, and means to actuatesaid device when the timer times out after a predetermined finite periodof time.
 13. The apparatus of claim 12 further provided with means todeactuate the device including a second timer and means to actuate thetimer and to allow it to operate as long as the pressure drop is withina preselected second range, and means to deactivate the device when thetimer times out after a predetermined finite period of time. 14.Apparatus for actuating a plurality of downhole devices carried by adrill string extending into a well bore, comprising timing means carriedby the drill string, means responsive to a preselected pressurecondition in the drill string to cause the timing means to operate whilesaid pressure condition exists, and means to actuate one of said deviceseach time the timing means times out.
 15. The apparatus of claim 14further provided with means for creating a surface detectable signal aseach device is actuated.
 16. The apparatus of claim 14 further providedwith second timing means, means responsive to a preselected pressurecondition in the drill string to cause the second timing means tooperate while said pressure condition exists, and means for deactivatingsaid devices when the second timer times out.
 17. The apparatus of claim14 in which the means to actuate one of said deviceS includes meansresponsive to rotation of the drill string to actuate additionaldevices.
 18. The apparatus of claim 14 further provided with means toprovide a preselected pressure differential for each of the devices whenactuated.